1. Field of the Invention
The invention relates to robotic end effectors, and more particularly, to end effector having a pair of gripping fingers which are suitable for engaging, retaining and releasing a plurality of tools and components, and has disposed therein a quick release locking mechanism.
2. Discussion of the Relevant Art
Automated production lines make the use of a plurality of robots to perform the numerous functions, such as inserting components, drilling, inserting screws and/or washers and moving components from one place to another and thereafter inserting them into particular printed circuit configurations or assemblies. With the variations in component size and the miniaturization of components it has become necessary to locate and insert these components with extreme accuracy so that a human being not be utilized during the production of the equipment. With the improved techniques introduced into the automated production line a single robotic arm is capable of performing many different functions by changing the tools acquired by the end effector disposed on the distal end of a robotic arm. Typical of these automatic production lines utilizing the concept of a robot having an arm capable of automatically changing tools affixed to the distal end of the robotic arm, generally referred to as an end effector, is disclosed in U.S. Pat. No. 4,809,425 issued on Mar. 7, 1989 to Mathew L. Monforte.
An end effector affixed on a robotic arm used in an automatic production line is described in detail in U.S. Pat. No. 4,591,198, issued on May 27, 1986 to Mathew L. Monforte and is incorporated herein in its entirety.
The automated production line utilizing multifunctional robots disclosed in these two patents overcome the shortcomings generally known to the art. The exchangeable end effector and cooperating tools utilized therein disclosed a simple, yet efficient means for acquiring and releasing tools and was a decided improvement over the known art.
U.S. Pat. No. 4,624,043 issued to David M. Bennett on Nov. 25, 1986 is another technique, commonly known as wrist change-out devices, utilized to acquire various types of tools and utilizes three translating devices disposed about the circumference of a circularly-shaped end effector which could acquire a limited number of tools, since the complete end effector is replaced and the wrist change-out member permanently mounted on the distal end of the robotic arm is not provided with fingers.
The disadvantages of wrist change-out devices include the requirement for a wrist plate to be mounted on every tool and/or end-effector to be acquired for operation on the robot. These plates add to the weight and length at the end of the robot arm which decreases the overall accuracy of the robot. Also, because of the size and thickness requirements of these plates, fitting them on new tools and end effectors usually requires much system engineering time and expense whenever production needs are initiated or changed. The length (thickness) and diameter of the wrist plate also takes up valuable real estate in the cell and tool storage bin and thereby limits the number of active and passive tools that can be nested for acquisition.
The flexible, multifunctional end effector and robotic cell disclosed in the '425 and '198 patents represent a breakthrough in automatic active and passive tool change-out devices by providing thin light-weight simple adapter plates with protrusions (keys) that fit through slots in the end effector fingers. Each gripper finger includes a locking assembly that engages the grooves of the inserted keys. The small light weight adapter keys can be easily mounted to any active or passive tool or finger shape for automatic acquisition by each of the gripper fingers to perform one of several designed robotic tasks.
This prior art was not free of problems. Tasks requiring high torque to be placed on the adapter keys, on occasion caused the top of the adapter plate to canter away from the finger surface. In some applications tool locking forces are insufficient for the designed tasks resulting from the small surface area of the locking piston on which the pneumatic drive forces are applied. Therefore, tool acquisition was not always as accurate and reliable as required.
Thus, the present invention overcomes shortcomings found in the prior art and provides advances over the prior art and includes a multifunctional end effector with two gripper fingers coupled to a drive assembly wherein each finger includes a quick lock/release mechanism that releasably acquires, with high precision and a mechanical advantage, a mating locking plate which becomes an integral part of each end effector finger. Another aspect of the invention includes mounting the lock/release mechanism including the drive mechanism therefor at the lower end of each end effector finger for better space utilization. A further aspect of the invention includes providing a substantial surface area for the lock/release mechanism drive so that the locking forces are sufficiently high to assure reliable acquisition integrity. In the instant invention, the mating locking plate surface is therefore compressed against the finger surface with great force, accuracy and integrity. Another aspect of the instant invention includes providing the mating locking plate with alignment elements to accurately align and fix the mating locking plate on the finger surface insuring the system's accuracy and integrity.
Therefore, it is an object of the present invention to provide an end effector having a pair of fingers, with a mechanism capable of quickly, accurately, reliably and firmly releasing and acquiring end effector active and passive tools.
It is another object of the present invention to provide an end effector which can, with great reliability, acquire and release an endless variety of tools and finger shapes for picking and placing any size and any shaped single or multiple part or parts.
Another object of the instant invention is to provide a multifunctional end effector in which each moveable finger thereof has a quick-release mechanism that cooperates with mating locking plates that easily mount on a desired tool or a plurality of tools.
Still another object of the invention is to standardize the robot/tool interface regardless of tool or part size or shape.
Yet another object of the invention is to enable the robot to be retooled or its cell functions to be re-engineered in hours instead of days.
It is yet another object of the present invention to provide an end effector mechanism having a pair of fingers with a locking and releasing mechanism on each finger capable of acquiring various types of tools.
It is still yet another object of the present invention to provide an end effector mechanism with a pair of fingers that may readily acquire two piece tools that are unsymmetrical.
It is still yet another object of the present invention to provide an end effector having a pair of fingers that may readily capture tools and is capable of providing electrical and pneumatic energy for the operation of the tools.
It is yet another object of the present invention to provide an end effector tool having a pair of fingers that incorporate sensing devices therein capable of providing a signal to the computer operating the associated robotic arm.
Other and further objects and advantages of the invention will become apparent with the following detailed description of exampled embodiments of the invention.